• WordNet 3.6
    • adj soporific inducing mental lethargy "a narcotic speech"
    • adj soporific sleep inducing
    • n soporific a drug that induces sleep
    • ***
Webster's Revised Unabridged Dictionary
    • n Soporific A medicine, drug, plant, or other agent that has the quality of inducing sleep; a narcotic.
    • a Soporific Causing sleep; tending to cause sleep; soporiferous; as, the soporific virtues of opium.
    • ***
Century Dictionary and Cyclopedia
    • soporific Tending to produce sleep.
    • n soporific Anything which causes sleep, as certain medicines.
    • ***
Chambers's Twentieth Century Dictionary
    • adj Soporific sō-pō-rif′ik making or causing sleep
    • n Soporific anything that causes sleep
    • ***


Webster's Revised Unabridged Dictionary
L. sopor, a heavy sleep (akin to somnus, sleep) + facere, to make. See Somnolent Fact


In literature:

Being unsuccessful, he had recourse to a soporific plant which he had recently discovered.
"The Giant of the North" by R.M. Ballantyne
Having some difficulty with getting to sleep, he resorted to soporifics and then, in a savage reaction, to stimulants.
"Security" by Poul William Anderson
Everyone is soporific and very restful.
"From Edinburgh to India & Burmah" by William G. Burn Murdoch
The strongest soporific in the world wouldn't give me sleep this night.
"The Death Shot" by Mayne Reid
But he has a very comfortable pew, in a very soporific church, and he is only half awake, and the echo dies away and leaves no sign.
"The Continental Monthly, Vol. 6, No 4, October, 1864" by Various
Converse has written many other hymn-tunes, which have taken their place among ecclesiastical soporifics.
"Contemporary American Composers" by Rupert Hughes
Like Washington Irving, these may have considered a good clean shave the best soporific.
"The Continental Monthly, Vol. 6, No. 6, December 1864" by Various
Might only sea air and exercise act as a soporific!
"Hopes and Fears scenes from the life of a spinster" by Charlotte M. Yonge
They're more soporific than bromide.
"The Strange Case of Mortimer Fenley" by Louis Tracy
We needed no other soporific.
"Crossing the Plains, Days of '57" by William Audley Maxwell

In news:

Following tradition, allayed by the smoked turkey's soporific effects, we engaged in some intellectual frivolity.
The Stanley Parable tells the story of a soporific office worker named Stanley.
Professional baseball's lachrymose and soporific spell.